SphinxExamples/src/Filtering/ImageFeature/FindZeroCrossingsInSignedImage/Code.cxx

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#include "itkImageFileReader.h"
#include "itkZeroCrossingImageFilter.h"
 
#include "itksys/SystemTools.hxx"
#include <sstream>
 
#ifdef ENABLE_QUICKVIEW
#  include "QuickView.h"
#endif
 
using ImageType = itk::Image<float, 2>;
 
static void
CreateImage(ImageType::Pointer image);
 
int
main(int argc, char * argv[])
{
  auto image = ImageType::New();
  if (argc < 2)
  {
    CreateImage(image);
  }
  else
  {
    image = itk::ReadImage<ImageType>(argv[1]);
  }
 
  using FilterType = itk::ZeroCrossingImageFilter<ImageType, ImageType>;
  auto filter = FilterType::New();
  filter->SetInput(image);
  filter->SetBackgroundValue(0);
  filter->SetForegroundValue(255);
 
#ifdef ENABLE_QUICKVIEW
  QuickView viewer;
  viewer.AddImage(
    image.GetPointer(), true, argc > 1 ? itksys::SystemTools::GetFilenameName(argv[1]) : "Generated image");
 
  std::stringstream desc;
  desc << "Zero Crossing";
  viewer.AddImage(filter->GetOutput(), true, desc.str());
 
  viewer.Visualize();
#endif
 
  return EXIT_SUCCESS;
}
 
void
CreateImage(ImageType::Pointer image)
{
  itk::Index<2> start;
  start.Fill(0);
 
  itk::Size<2> size;
  size.Fill(100);
 
  itk::ImageRegion<2> region(start, size);
 
  image->SetRegions(region);
  image->Allocate();
  image->FillBuffer(-1);
 
  // Make half of the image negative
  for (unsigned int i = 0; i < 100; ++i)
  {
    for (unsigned int j = 0; j < 50; ++j)
    {
      itk::Index<2> index;
      index[0] = i;
      index[1] = j;
      image->SetPixel(index, 1);
    }
  }
}